A while back I wrote about some issues with converting
a two-disk RAID system to a one-disk system, but just to recap:

We knew were were moving to Finland.

The shared/main computer we used in the UK was old and slow.

A new computer in Finland would be more expensive than it should be.

Equally transporting a big computer from the UK would also be silly.

In the end we bought a small form-factor PC, with only a single drive
and I moved one of the two drives from the old machine into it. Then
converted it to run happily with only a single drive, and not email
every day to say "device missing".

So there things stood, we had a desktop with a single drive, and I
ensured that I took full daily backup via
attic.

Over Chrismas the two-year old drive failed. To the extent I couldn't
even get it to be recognized by the BIOS, and thus couldn't pull data
off it. Time to test my backups in anger! I bought a new drive,
installed a minimal installation of the Jessie release of Debian onto the system, and then
ran:

cd /
.. restore latest backup ..

Two days later I'd pulled 1.3Tb over the network, and once I fixed up
grub, /etc/fstab, and a couple of niggles it all just worked.
Rebooted to make sure the temporary.home hostname, etc, was all
gone and life was good.

Restored backup! No errors! No data-loss! Perfect!

The backup-script I use every day was very very good at making sure
nothing was missed: